Placobdella parasitica (Say, 1824) is one of the most commonly encountered turtle leeches in North America. Molecular analysis of individuals of P. parasitica representing various populations throughout its range in North America using the cytochrome c oxidase subunit I gene, revealed the presence of nine distinct groups: (1) P. parasitica sensu stricto containing members, including the neotype specimen, occurring broadly throughout the central United States westward from the Mississippi River to the Rocky Mountains and throughout southern Ontario, Canada, and the upper midwestern United States as far east as New York State; (2) West Virginia; (3) Mississippi/Alabama; (4) Northeast, including New York, Massachusetts, and Vermont; (5) New England, including Rhode Island, Massachusetts, and Connecticut; (6) North Carolina/West Virginia; (7) South Carolina; (8) Tennessee; and (9) Florida. Both neighbor-joining and maximum likelihood analyses recovered an east-west split along the Appalachian Mountains with groups 1–3 clustering together and groups 4–9 clustering separately, with the exception of group 8 (Tennessee) that placed with the eastern groups. Group 1 includes specimens from a broad geographic distribution, yet with relatively low genetic variation, a pattern observed in other glossiphoniid species in North America. The groups with members east of the Appalachian Mountains are more tightly clustered by locality. This leech species is known to parasitize several turtle species, including Chrysemys picta, the painted turtle that originated in the central Gulf Coast region and dispersed northward representing a recolonization after Pleistocene glaciation. The neighbor-joining tree and pairwise distance data could suggest that P. parasitica has a similar phylogeographic pattern and dispersal history with its turtle hosts. In view of the morphological uniformity among the various groups, P. parasitica is provisionally considered to be a widely distributed, molecularly variable species.

Placodella michiganensis (Sawyer, 1972) was originally described from free-living individuals collected from Mill Creek, St. Joseph County, Michigan, USA. The acquisition of contemporary specimens from its type locality has facilitated redescription of P. michiganensis. Placobdella michiganensis does not have a confusing taxonomic history like many other members of the genus Placobdella as it has only been collected two other times since its description. Placodella michiganensis is distinguished from its congeners by its five rows of whitish single-tipped papillae, genital and pre-anal patches, five pre-anal papillae, and absence of a dark dorsal-medial line. Placobdella michiganensis is a morphologically distinct species with a 16.0% to 22.0% difference in cytochrome c oxidase subunit I sequence data among congeners.

This study documented and assessed benthic macroinvertebrate communities on a section of Canyon Creek through Tensleep Preserve in Washakie County, Wyoming, USA. Data for these communities are compared with previous samples collected downstream on agricultural land, as well as upstream and downstream from two subterranean, limestone sinks on the preserve. A shift from Plecoptera, Coleoptera, and Ephemeroptera to mainly Ephemeroptera to mainly Trichoptera was observed from the uppermost to the lowermost sites; Chironomidae and Diptera dominated the previously sampled section. High proportions of scrapers in sampled communities on the preserve beginning downstream of the upstream sink system suggested a prevalence of autochthonous detritus over allochthonous detritus at these sites. Macroinvertebrate community compositions and calculated metrics indicated high water quality for sites on the preserve and lower water quality for the agriculturally impacted sites. Ten taxa recorded from samples between the subterranean sinks were not recorded elsewhere. The mayfly Ameletus validus was abundant at the exit of the upper sink system at which the substrate was lined with irregular limestone slabs, and this taxon may be limited to the interior of this sink. Neothremma is identified as a feasible indicator taxon for climate change.